1. Field of the Invention
The present invention relates to a golf ball composition from which golf balls having an especially good rebound and an outstanding flight performance can be obtained. The invention also relates to a golf ball formed using such a composition.
2. Prior Art
In order to confer golf balls with an excellent rebound, various improvements have hitherto been carried out, not only on the ball construction, but also on the materials from which the ball is formed.
For example, in order to develop a polymeric material having high thermal properties (e.g., thermal stability) and mechanical properties (e.g., tensile modulus, flexural modulus), JP-A 2000-313710 discloses a catalyst composition which is capable of producing a conjugated diene polymer having a high cis-1,4 structure content in the microstructure and having a narrow molecular weight distribution. JP-A 2002-282393 and JP-A 2002-338737 describe solid golf balls having a good flight performance, in which balls a solid core has been formed using a polybutadiene rubber obtained with, for example, the catalyst composition described in JP-A 2000-313710.
International Application No. 2006/049016 describes art which, by using an yttrium compound as a polymerization catalyst in a catalyst composition for polymerizing conjugated diene polymers, reduces the level of aluminum residues at the time of polymerization. However, from the standpoint of the rebound and other properties of golf balls, further improvements are desired.
Other prior art relating to the present invention is disclosed in, for example, JP-A 2002-239034, JP-A 2003-154033, JP-A 2003-190333, JP-A 2003-225327, JP-A 2005-089551, JP-A 2005-111049, JP-A 2007-222196, JP-A 2008-161345, U.S. Pat. No. 6,277,920, and U.S. Pat. No. 7,244,194.
In view of the foregoing, it is an object of the present invention to provide a golf ball composition from which golf balls having a good rebound and an excellent flight performance can be obtained. A further object is to provide a golf ball formed using such a composition.